The invention relates to a nonwoven textile sponge for use in the medical and/or hygienic field. Such products usually consist of at least one absorbent fiber layer, mixed in some cases with binding fibers, and at least one waterrepellent outer fiber layer of nonwoven fabric covering it at least on the wound side, through perforations being present over the entire surface of the sponge. The present invention is also in a method for the production of the inventive sponge.
Absorbent textile pads known as sponges are needed in medicine and in hygiene for use as surgical bandages, and as protective or wiping material. In wound treatment, a woven cotton gauze has the disadvantages that it adheres to the wound and has an unsatisfactorily low ability to absorb wound secretions. To reduce the tendency to adhere, unfolded compresses of the absorbent layer of first-aid bandages are covered with moisture-repellent woven synthetic fiber layers.
Thus, in European Patent No. 77,034, a sponge is described, which is made of a core of highly absorbent material with a two-layer covering on at least the side to be applied to the wound. The layer adjacent the core consists of a heat-sealing nonwoven and the outside layer consists of polypropylene fabric with a mesh structure. This latter nonwoven fabric is said to facilitate the absorption of wound secretions into the absorbent layers, due to its sufficiently large, irregular-edged openings, better than perforated polypropylene films, without any clogging of the pores. The heat-sealing nonwoven joining the outer mesh structure to the absorbent layer is thus placed very closely against the wound. The two-layer envelope can be welded at its edges to form a surgical sponge.
On account of this outer, two-layer sandwich construction, however, the ability of the sponges to fold is impaired, although this is often needed for improved absorbency, since under heavy stress they often tend to break at the creases in the wound coverings.
To remedy this, very bulky, non-folding sponges must be made available, which are difficult to handle, and whose packaging costs are considerably increased.
Furthermore, the fact that the polypropylene fabric layer has to be manufactured prior to the manufacture of the pad contributes considerably to the cost increase.
Covering with nonweldable nonwoven covering materials is not feasible on account of the dispersions of polymer binding agents which are then necessary and their content of medically unacceptable soluble additives.
French Patent Application FR-A No. 2,536,432 shows a hydraulic perforating apparatus and a method whereby perforated nonwovens, containing no binding agent and made of mostly cotton fibers, can be made with attritionresistant surfaces, wherein the fibers are entangled with one another by needling with very high-pressure water jets. These products distinguish themselves from cotton gauze by their approximately 50% higher capacity for the absorption of aqueous fluids.
The amount of energy required for the high-pressure water jet needling, however, is very great. This product also tends to stick to the wound on account of the not-inconsiderable content of cotton at the surface.
It is an object of the present invention to provide an absorbent, nonwoven textile sponge whose absorbency is equal to that of perforated rayon and cotton nonwovens, but which contains no binding agent of any kind, is resistant to attrition and free of fluff, which does not adhere to the wound and can be folded as many times as required, without harm. It is also an object of the invention to provide a sponge that can be used in many applications especially in medicine, but also in the field of hygiene. Thus, the formerly incompatible advantages of known medical absorbent articles are to be combined in a single product.
Furthermore, an object of the invention is in providing a low-cost and simple method for the production of such a sponge, whereby the technical complexity and cost of water-jet needling and the use of a two-layer cover of nonwoven and woven materials can be avoided, while dispersing with requiring a binding agent for consolidation.